Real-time online surge current monitoring system

Abstract

The utility model discloses a real-time online surge current monitoring system, which comprises a sensing module, an acquisition module, a communication module and an upper computer, and is characterized in that the sensing module is used for measuring surge current; the communication module is used for data interaction; the acquisition module is used for acquiring and processing a signal output by the sensing module, the acquisition module uploads the processed signal to the server through the communication module, a user remotely monitors the surge current condition by inquiring information of the server in real time, and the acquisition module is electrically connected with the upper computer. The upper computer is used for controlling the acquisition module and displaying an output signal of the acquisition module; the sensing module comprises a hollow Rogowski coil and a composite integrator, the hollow Rogowski coil is used for collecting current signals, and the composite integrator is used for carrying out bandwidth adjustment on output signals of the hollow Rogowski coil. The surge current monitoring device has the advantages of wide measurement frequency band and large current measurement range, and can realize remote real-time on-line monitoring of the surge current condition of the electrical equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of surge current detection, in particular to a real-time online surge current monitoring system. Background Art

[0002] Surge current refers to the current characteristics of electrical equipment within a short period of time after it is turned on. It is very important to the safety of both the power grid and electrical equipment. In view of the mechanism of surge current generation, domestic and foreign electrical companies and research institutions have been studying how to better suppress surge current. In engineering, it is usually necessary to suppress the impact of surge current on equipment as much as possible.

[0003] In many fields of the electrical industry, the handling of surge current is critical. In particular, the monitoring of surge current plays an important role in the safety of electrical equipment and is a key technology for studying surge current suppression. For the monitoring of surge current, there are currently measurement methods such as shunt method, optical method and Rogowski coil. The use of Rogowski coil is an indirect measurement method that does not affect the transmission of current and has excellent development prospects. However, the general surge current monitoring system requires on-site measurement and obtains results from the site, which makes it inconvenient to apply to power grids and areas that require remote operations; in addition, the existing technology is often limited by the measurement current frequency band, and various different working scenarios pose challenges to the flexibility of parameter adjustment of the monitoring system. Therefore, it is urgent to design a real-time online surge current monitoring system with a wider measurement frequency band, a wider range of current measurement and flexibility of use, so that users can remotely monitor the surge current of electrical equipment more efficiently and conveniently. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art and to provide a real-time online surge current monitoring system, which has the advantages of a wide measurement bandwidth and a large measurement current range and can realize real-time online remote monitoring of the surge current of electrical equipment.

[0005] The purpose of the utility model is achieved through the following technical solutions: a real-time online surge current monitoring system, including a sensing module, an acquisition module, a communication module and a host computer, the sensing module is used to measure the surge current; the communication module is used for data interaction; the acquisition module is used to acquire and process the signal output by the sensing module, the acquisition module uploads the processed signal to the server through the communication module, and the user remotely monitors the surge current by querying the information of the server in real time, the acquisition module is electrically connected to the host computer, the host computer is used to control the acquisition module and display the output signal of the acquisition module; the sensing module includes a hollow Rogowski coil and a composite integrator, the hollow Rogowski coil is used to acquire the current signal, and the composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil.

[0006] Preferably, the composite integrator is composed of a self-integrating part and a second-order passive external integrating part connected in parallel therewith, wherein the self-integrating part is a self-integrating resistor R t , the self-integrating resistance R t connected in parallel to the terminal of the hollow Rogowski coil; the second-order passive external integral part includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor and a second capacitor, wherein the first resistor, the third resistor and the fifth resistor are connected in a triangle, the first capacitor and the fourth resistor are connected in series, the second capacitor and the second resistor are connected in series, and the two ends of the fifth resistor are respectively connected to the fourth resistor and the second resistor; the connection end of the first resistor and the third resistor forms the input end of the second-order passive external integral part, the connection end of the first resistor, the fifth resistor and the second resistor forms the output end of the second-order passive external integral part, and the connection end of the first capacitor and the second capacitor forms the common end of the second-order passive external integral part; the output end of the second-order passive external integral part is connected to the input end of the acquisition module.

[0007] Preferably, the composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil, specifically including setting each circuit parameter in the sensor module according to the following conditions:

[0008] L0 / R t =R2C1, R1≥10R2,

[0009] Where L0 is the self-inductance of the Rogowski coil, R t is the resistance value of the self-integrating resistor, C1 is the capacitance value of the first capacitor, and R1 and R2 are the resistance values ​​of the first resistor and the second resistor respectively.

[0010] Preferably, the composite integrator includes a passive integration part and an active integration part, wherein the passive integration part is an RC integration circuit composed of a resistor R0 and a capacitor C0, and the active integration part includes a resistor R a, resistor R b , capacitor C a and operational amplifier L; the hollow Rogowski coil is divided into two branches after passing through resistor R0, one of which is connected to capacitor C0 and then grounded, and the other branch is connected to the in-phase input terminal of operational amplifier L, the resistor R b and capacitor C a After the parallel connection, one end is connected to the inverting input end of the operational amplifier L, and the other end is connected to the output end of the operational amplifier L, and the inverting input end of the operational amplifier L is connected to the inverting input end of the operational amplifier L through the resistor R a The output end of the operational amplifier L is connected to the input end of the acquisition module.

[0011] Preferably, the composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil, specifically including the resistor R0, the capacitor C0, the resistor R a And capacitor C a The value of satisfies the condition: R0C0=R a C a .

[0012] Preferably, the hollow Rogowski coil adopts a hollow frame of non-magnetic material, the enameled wire package is loosely wound on the hollow frame, and the enameled wire package and the hollow frame are covered with a shielding shell.

[0013] Preferably, the acquisition module includes a data acquisition card, and the data acquisition card transmits signals to a host computer by connecting to a serial port, a USB interface, a PCI bus or a network.

[0014] Preferably, the communication module includes a 4G router, and the acquisition module transmits the signal to the server via the 4G router.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] (1) The utility model provides a real-time online surge current monitoring system. By adopting a hollow Rogowski coil to measure surge current, the system can detect a wider range of surge currents. The composite integrator can be used to broaden the measurement frequency band. The host computer can be used to set and display parameters, thereby improving the flexibility of the monitoring system. The communication module can transmit the signal of the acquisition module to the server in real time, thereby realizing remote real-time online monitoring of the surge current. This system is beneficial for relevant professionals to study the variation law of surge current and reduce the difficulty and cost of on-site testing. The system has important practical application significance in the electrical field.

[0017] (2) The composite integrator of the utility model effectively reduces the lower limit cutoff frequency of the air-core Rogowski coil measuring current by adopting a hybrid integration design of a self-integration part combined with a second-order passive external integration part, or adopts a composite integration design of an RC integration circuit and an active integration part, thereby obtaining a wider measurement bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The utility model is a structural block diagram of a real-time online surge current monitoring system.

[0019] Figure 2 This is a schematic diagram of the structure of the composite integrator of Example 1 of the utility model.

[0020] Figure 3 It is the current waveform collected by the acquisition card displayed by the host computer of the utility model.

[0021] Figure 4 This is a schematic diagram of the structure of the composite integrator of Example 2 of the present utility model. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] Example 1

[0024] like Figure 1 The figure shows a structural block diagram of a real-time online surge current monitoring system, which includes a sensing module, an acquisition module, a communication module and a host computer. The sensing module is used to measure surge current; the communication module is used for data exchange; the acquisition module is used to acquire and process the signal output by the sensing module, and the acquisition module uploads the processed signal to the server through the communication module. The user can remotely monitor the surge current by querying the information of the server in real time. The acquisition module is electrically connected to the host computer, and the host computer is used to control the acquisition module and display the output signal of the acquisition module; the sensing module includes a hollow Rogowski coil and a composite integrator, the hollow Rogowski coil is used to acquire current signals, and the composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil.

[0025] Specifically, the output end of the sensing module is connected to the input end of the acquisition module. After measuring the current signal, the sensing module transmits the signal to the acquisition module. The acquisition module transmits the signal to the server via the communication module, and the acquisition module is electrically connected to the host computer, so that the monitoring parameters can be set and the collected signals can be displayed through the software of the host computer. The utility model measures the surge current by using a hollow Rogowski coil. The hollow Rogowski coil uses a hollow skeleton of non-magnetic material. The lacquered wire package is loosely wound on the hollow skeleton. The lacquered wire package and the hollow skeleton are covered with a shielding shell. Compared with the coil with a magnetic core, there is a problem of magnetic core saturation when measuring large current. The hollow core coil does not have the problem of magnetic core saturation, and the current amplitude that can be measured is larger; the composite integrator is used to widen the measurement frequency band, and the parameters are set and displayed through the host computer, which improves the flexibility of the monitoring system. The signal of the acquisition module is transmitted to the server in real time through the communication module to realize remote real-time online monitoring. In summary, the utility model has the advantages of wide measurement bandwidth, large measurement current range and wireless transmission function, and is of great significance to the field of remote real-time online monitoring of surge current.

[0026] The composite integrator is composed of a self-integrating part and a second-order passive external integrating part connected in parallel. The self-integrating part is a self-integrating resistor R t , the self-integrating resistance R t Connected in parallel to the terminals of the hollow Rogowski coil; Figure 2 As shown, the second-order passive external integral part includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor and a second capacitor, wherein the first resistor, the third resistor and the fifth resistor are connected in a triangle, the first capacitor and the fourth resistor are connected in series, the second capacitor and the second resistor are connected in series, and the two ends of the fifth resistor are respectively connected to the fourth resistor and the second resistor; the connection end of the first resistor and the third resistor forms the input end of the second-order passive external integral part, the connection end of the first resistor, the fifth resistor and the second resistor forms the output end of the second-order passive external integral part, and the connection end of the first capacitor and the second capacitor forms the common end of the second-order passive external integral part; the output end of the second-order passive external integral part is connected to the input end of the acquisition module.

[0027] The composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil, specifically including setting each circuit parameter in the sensor module according to the following conditions:

[0028] L0 / R t =R2C1, R1≥10R2,

[0029] Where L0 is the self-inductance of the Rogowski coil, R tis the resistance value of the self-integrating resistor, C1 is the capacitance value of the first capacitor, and R1 and R2 are the resistance values ​​of the first resistor and the second resistor respectively.

[0030] Specifically, the current measured by the traditional self-integrating Rogowski coil used in the prior art is limited by the frequency band. The lower limit cutoff frequency measured by the traditional self-integrating Rogowski coil is: When the conditions are met: L0 / R t =R2C1, the lower cut-off frequency of the first-order passive external integral Rogowski coil is: When the condition is met: R1>R2, then: That is, when R1>R2, compared with the traditional self-integrating Rogowski coil, the lower cutoff frequency of the Rogowski coil can be greatly extended through the first-order passive external integration, and the measurement lower cutoff frequency of the first-order passive external integration Rogowski coil is at least reduced to R2 / R1 times of the traditional self-integrating Rogowski coil.

[0031] The composite integrator of the utility model adopts a second-order passive external integration, and satisfies the condition L0 / R t =R2C1 and R1>>R2, the amplitude-frequency characteristics basically the same as those of the first-order passive external integral Rogowski coil can be obtained, that is, the lower limit cutoff frequency corresponding to the current measured by the sensor module designed with the second-order passive external integral is: The lower limit cutoff frequency of the current measured by the utility model is at least reduced to R2 / R1 times the lower limit cutoff frequency of the traditional self-integrating Rogowski coil. In this embodiment, the specific value relationship between R1 and R2 is: R1≥10R2. This setting effectively reduces the lower limit cutoff frequency of the current measured by the hollow Rogowski coil and widens the frequency band of the measured current.

[0032] The acquisition module includes a data acquisition card, and the data acquisition card transmits signals to a host computer by connecting to a serial port, a USB interface, a PCI bus or a network.

[0033] Specifically, the data acquisition card is used to collect, process and transmit the signal output by the sensor module. In this embodiment, the data acquisition card is connected to the host computer by means of a network cable.

[0034] The communication module includes a 4G router, and the acquisition module transmits the signal to the server through the 4G router. Specifically, the 4G router can realize remote real-time transmission of data, solve the boundary problem of on-site testing, and improve the timeliness of user monitoring.

[0035] like Figure 3The figure shows the current waveform collected by the acquisition card displayed by the host computer using the utility model. In this embodiment, an underdamped oscillation wave with an amplitude of 90kA is detected, and the current is measured using a hollow Rogowski coil. The composite integrator is adjusted and the oscillation wave is collected by the acquisition card. After the parameters are set by the software of the host computer, including adjusting the trigger mode, trigger level, waveform cache points and sampling rate of the current measurement, the measured waveform is finally displayed by the host computer, i.e., the PC, and the corresponding waveform data is obtained. Figure 3 It can be seen that the final tested waveform is consistent with the measured current and the measurement is accurate.

[0036] Example 2

[0037] The difference between the second embodiment and the first embodiment is that the structure of the composite integrator is different. Figure 4 As shown, in this embodiment, the composite integrator includes a passive integration part and an active integration part. The passive integration part is an RC integration circuit composed of a resistor R0 and a capacitor C0, and the active integration part includes a resistor R a , resistor R b , capacitor C a and operational amplifier L; the hollow Rogowski coil is divided into two branches after passing through resistor R0, one of which is connected to capacitor C0 and then grounded, and the other branch is connected to the in-phase input terminal of operational amplifier L, the resistor R b and capacitor C a After the parallel connection, one end is connected to the inverting input end of the operational amplifier L, and the other end is connected to the output end of the operational amplifier L, and the inverting input end of the operational amplifier L is connected to the inverting input end of the operational amplifier L through the resistor R a The output end of the operational amplifier L is connected to the input end of the acquisition module. The composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil, specifically including the resistor R0, the capacitor C0, the resistor R a And capacitor C a The value of satisfies the condition: R0C0=R a C a .

[0038] Specifically, the composite integrator of the utility model adopts a composite integration design of an RC integration circuit and an active integration part, the input voltage of the passive integration part is e(t), and the output voltage of the active integration part is u out (t), the lower cut-off frequency of the air-core Rogowski coil current measurement can be reduced by adjusting the composite integrator, so that the current with a lower frequency can be measured.

[0039] The above-mentioned specific implementation modes are preferred embodiments of the present invention and cannot be used to limit the present invention. Any other changes or other equivalent replacement methods that do not deviate from the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. A real-time online surge current monitoring system, characterized in that: The invention comprises a sensing module, an acquisition module, a communication module and a host computer, wherein the sensing module is used to measure surge current; the communication module is used for data exchange; the acquisition module is used to acquire and process the signal output by the sensing module, and the acquisition module uploads the processed signal to a server through the communication module, and a user remotely monitors the surge current by querying the information of the server in real time; the acquisition module is electrically connected to the host computer, and the host computer is used to control the acquisition module and display the output signal of the acquisition module; the sensing module comprises an air-core Rogowski coil and a composite integrator, the air-core Rogowski coil is used to acquire the current signal, and the composite integrator is used to adjust the bandwidth of the output signal of the air-core Rogowski coil.

2. A real-time online surge current monitoring system according to claim 1, characterized in that: The composite integrator is composed of a self-integrating part and a second-order passive external integrating part connected in parallel. The self-integrating part is a self-integrating resistor R t , the self-integrating resistance R t connected in parallel to the terminal of the hollow Rogowski coil; the second-order passive external integral part includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor and a second capacitor, wherein the first resistor, the third resistor and the fifth resistor are connected in a triangle, the first capacitor and the fourth resistor are connected in series, the second capacitor and the second resistor are connected in series, and the two ends of the fifth resistor are respectively connected to the fourth resistor and the second resistor; the connection end of the first resistor and the third resistor forms the input end of the second-order passive external integral part, the connection end of the first resistor, the fifth resistor and the second resistor forms the output end of the second-order passive external integral part, and the connection end of the first capacitor and the second capacitor forms the common end of the second-order passive external integral part; the output end of the second-order passive external integral part is connected to the input end of the acquisition module.

3. A real-time online surge current monitoring system according to claim 2, characterized in that: The composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil, specifically including setting each circuit parameter in the sensor module according to the following conditions: L0 / R t =R2C1,R1≥10R2, Where L0 is the self-inductance of the Rogowski coil, R t is the resistance value of the self-integrating resistor, C1 is the capacitance value of the first capacitor, and R1 and R2 are the resistance values ​​of the first resistor and the second resistor respectively.

4. A real-time online surge current monitoring system according to claim 1, characterized in that: The composite integrator includes a passive integration part and an active integration part. The passive integration part is an RC integration circuit composed of a resistor R0 and a capacitor C0. The active integration part includes a resistor R a , resistor R b , capacitor C a and operational amplifier L; the hollow Rogowski coil is divided into two branches after passing through resistor R0, one of which is connected to capacitor C0 and then grounded, and the other branch is connected to the in-phase input terminal of operational amplifier L, the resistor R b and capacitor C a After the parallel connection, one end is connected to the inverting input end of the operational amplifier L, and the other end is connected to the output end of the operational amplifier L, and the inverting input end of the operational amplifier L is connected to the inverting input end of the operational amplifier L through the resistor R a The output end of the operational amplifier L is connected to the input end of the acquisition module.

5. A real-time online surge current monitoring system according to claim 4, characterized in that: The composite integrator is used to adjust the bandwidth of the output signal of the hollow Rogowski coil, specifically including the resistor R0, the capacitor C0, the resistor R a and capacitor C a The value of satisfies the condition: R0C0=R a C a .

6. A real-time online surge current monitoring system according to claim 1, characterized in that: The hollow Rogowski coil adopts a hollow frame made of non-magnetic material, and the enameled wire package is loosely wound on the hollow frame. The enameled wire package and the hollow frame are covered with a shielding shell.

7. A real-time online surge current monitoring system according to claim 1, characterized in that: The acquisition module includes a data acquisition card, and the data acquisition card transmits signals to a host computer by connecting to a serial port, a USB interface, a PCI bus or a network.

8. The real-time online surge current monitoring system according to claim 1, characterized in that: The communication module includes a 4G router, and the acquisition module transmits the signal to the server via the 4G router.

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